DVB systems distribute data using a variety of approaches, including:
Satellite: DVB-S, DVB-S2 and DVB-SH
DVB-SMATV for distribution via SMATV
Cable: DVB-C, DVB-C2
Terrestrial television: DVB-T, DVB-T2
Digital terrestrial television for handhelds: DVB-H, DVB-SH
Microwave: using DTT (DVB-MT), the MMDS (DVB-MC), and/or MVDS standards (DVB-MS)
These standards define the physical layer and data link layer of the distribution system. Devices interact with the physical layer via a synchronous parallel interface (SPI), synchronous serial interface (SSI), or asynchronous serial interface (ASI). All data is transmitted in MPEG transport streams with some additional constraints (DVB-MPEG). A standard for temporally-compressed distribution to mobile devices (DVB-H) was published in November 2004.
These distribution systems differ mainly in the modulation schemes used and error correcting codes used, due to the different technical constraints. DVB-S (SHF) uses QPSK, 8-PSK or 16-QAM. DVB-S2 uses QPSK, 8-PSK, 16-APSK or 32-APSK, at the broadcasters decision. QPSK and 8-PSK are the only versions regularly used. DVB-C (VHF/UHF) uses QAM: 16-QAM, 32-QAM, 64-QAM, 128-QAM or 256-QAM. Lastly, DVB-T (VHF/UHF) uses 16-QAM or 64-QAM (or QPSK) in combination with (C)OFDM and can support hierarchical modulation.
The DVB-T2 specification was approved by the DVB Steering Board in June 2008 and sent to ETSI for adoption as a formal standard. ETSI adopted the standard on 9 September 2009.
The DVB-T2 standard gives more robust TV reception and increases the possible bit rate by over 30% for single transmitters (as in the UK) and should increase the max. bit rate by over 50% in large single-frequency networks (as in Germany, Sweden).
DVB has established a 3D TV group (CM-3DTV) to identify "what kind of 3D-TV solution does the market want and need, and how can DVB play an active part in the creation of that solution?". The CM-3DTV group held a DVB 3D-TV Kick-off Workshop in Geneva on 25 January 2010, followed by the first CM-3DTV meeting the next day. DVB now defines a new standard for 3D video broadcast: DVB 3D-TV.
Modes and features of latest DVB-x2 system standards in comparison:
DVB-S2 DVB-T2 DVB-C2
Input Interface Multiple Transport Stream and Generic Stream Encapsulation (GSE) Multiple Transport Stream and Generic Stream Encapsulation (GSE) Multiple Transport Stream and Generic Stream Encapsulation (GSE)
Modes Variable Coding & Modulation and Adaptive Coding & Modulation Variable Coding & Modulation Variable Coding & Modulation and Adaptive Coding & Modulation
FEC LDPC + BCH 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10 LDPC + BCH 1/2, 3/5, 2/3, 3/4, 4/5, 5/6 LDPC + BCH 1/2, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10
Modulation Single Carrier QPSK with Multiple Streams OFDM absolute OFDM
Modulation Schemes QPSK, 8-PSK, 16-APSK, 32-APSK QPSK, 16-QAM, 64-QAM, 256-QAM 16- to 4096-QAM
Guard Interval Not Applicable 1/4, 19/256, 1/8, 19/128, 1/16, 1/32, 1/128 1/64 or 1/128
Fourier transform size Not Applicable 1k, 2k, 4k, 8k, 16k, 32k DFT 4k Inverse FFT
Interleaving Bit-Interleaving Bit- Time- and Frequency-Interleaving Bit- Time- and Frequency-Interleaving
Pilots Pilot symbols Scattered and Continual Pilots Scattered and Continual Pilots